1. Field of the Invention
The present invention relates to a method of manufacturing thread-stitched books. The method includes gathering folded printed sheets into blocks and later binding the printed sheets into a book block by sewing the individual printed sheets together.
The present invention further relates to an arrangement for carrying out the above-described method. The arrangement includes a gathering unit with several feeder stations for different printed sheets and at least one subsequently arranged book sewing machine.
2. Description of the Related Art
In a machine arrangement for thread-stitching of book blocks disclosed in CH-A-503,595, blocks manufactured from printed sheets in a gathering machine or device are transferred at the stack discharge or delivering unit to a coplanar conveyor belt. Feeders of a book sewing machine for the blocks are arranged along the conveyor belt. Operating personnel load the blocks arriving on the conveyor belt onto the feeders. In a method carried out on the machine arrangement of CH-A-503,595, the blocks are placed on pallets at the end of the gathering machine and the pallets are moved into a storage area until the blocks are further processed in the book sewing machines. The filled pallets are transported from the storage area to the feeders of the book sewing machines and the blocks are manually placed in the feeders.
In newer arrangements, a machine is used for loading the book sewing machine directly from the gathering unit.
The manual loading is very labor intensive because the feeders of the book sewing machine or machines have to be loaded and/or the printed sheets gathered into blocks have to be placed into intermediate storage. The intermediate storage is necessary because of the output ratio between gathering unit and book sewing machine, wherein the gathering unit is capable of gathering a plurality of blocks during the time that the book sewing machine is capable of finishing a book block. The reason for the substantially longer processing time in the book sewing machine is the fact that each individual printed sheet of a block is being sewed. In other words, during each work cycle of the gathering unit, a block is made available at the delivery unit which cannot be processed completely by the book sewing machine within the same period of time because the capacity of the book sewing machine is smaller.
On the other hand, it would not be economical to increase the sewing capacity by increasing the number of book sewing machines and by providing extensive conveyor units when a greater order is to be filled.
When the gathering unit and the book sewing machine or machines are directly connected, an economical manufacture is only possible if a smaller number of units is to be produced, so that an intermediate storage of the blocks is not necessary. Other disadvantages of known arrangements of the above-described type are described in the relevant technical literature.